A New Look at 'Ocean Worlds': James Webb Space Telescope Will Target Europa and Enceladus

By Paul Scott Anderson, on August 31st, 2017

An example of possible spectroscopy results from one of Europa’s water vapor plumes. Image Credit: NASA-GSFC/SVS/Hubble Space Telescope/Stefanie Milam/Geronimo Villanueva

NASA’s upcoming James Webb Space Telescope (JWST) will be used to study two of the most fascinating moons in our Solar System – Europa and Enceladus, also known as “ocean worlds” since both have global oceans of water beneath their outer icy surfaces. The new observations will help scientists learn more about conditions on these worlds and guide the development of future robotic missions.

Both moons are exciting targets since Europa’s surface has deposits of minerals thought to have come up from the ocean below, and Enceladus has huge plumes of water vapor erupting through fissures in the icy surface, originating from the subsurface ocean. Europa may also have plumes, which have been tentatively identified but not confirmed yet. Enceladus’ plumes also contain organic compounds of various complexities, which were sampled directly by the Cassini spacecraft multiple times.

“We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest,” said astronomer Heidi Hammel, executive vice president of the Association of Universities for Research in Astronomy (AURA).

Astronomers will use Webb’s near-infrared camera (NIRCam) to take high-resolution images of Europa’s surface, to search for hot regions related to plumes and active geological processes. If a plume is found, they can then use Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI) to analyze the plume’s composition.

“Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water?” asked Villanueva. “Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.”

JWST will be able to study Enceladus’ plumes and surface in a similar manner, even though it is about 10 times smaller than Europa as seen by the telescope.

For both moons, a focus will be to search for organic signatures such as methane, methanol, and ethane in the plumes. Evidence of life itself, like microbes, would be more difficult since some life-like processes could also have a geological explanation.

Composite image showing the possible water vapor plumes near the south pole of Europa, at about the 7 o’clock position. The image of Europa, from the Galileo and Voyager missions, is superimposed on the Hubble data. Image Credit: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

Diagram of an interior cross-section of the crust of Enceladus, showing how hydrothermal activity is thought to be causing the plumes of water vapor on the surface. Image Credit: NASA-GSFC/SVS/NASA/JPL-Caltech/Southwest Research Institute

The water vapor plumes of Enceladus, as seen by the Cassini spacecraft. Photo Credit: NASA/JPL-Caltech

“We only expect detections if the plumes are particularly active and if they are organic-rich,” Villanueva noted.

JWST is the successor to the Hubble Space Telescope (HST) and will be the most powerful space-based telescope ever built. It is an international project led by NASA, along with the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Even if JWST isn’t able to find signs of life on either moon, it will be another huge step in understanding what conditions are like, both on their surfaces and below the ice in the oceans themselves, building on results from spacecraft such as Galileo and Cassini. It will help prepare the way for future, more advanced probes on the drawing boards now which may be able to answer that question of whether life has ever existed on (in) these far-off ocean worlds.

39 comments to A New Look at ‘Ocean Worlds’: James Webb Space Telescope Will Target Europa and Enceladus

There will come a time in the future where mankind discovers multiple remnants of life throughout our solar system and beyond. Such discoveries will settle once and for all the question “Are we alone?”

Thank you once again Paul Scott Anderson for another thought provoking space science article!

Europa is about 3,100 km in diameter which a bit less than the 3,474 km diameter of our Moon. NASA’s robotic Europa Clipper mission will look for evidence of life on that large moon of Jupiter.

“Europa receives 5.4 Sv (540 rem) of radiation per day,[2] which is approximately 1,800 times the average annual (yearly) dose of a human on earth at sea level[3]. Humans exposed to this level of radiation for one day would have greater than 50% mortality rate within 30 days.”

Enceladus is about 500 km in diameter and is a moon of far distant Saturn.

What could happen if the James Webb Space Telescope and our various robotic spacecraft eventually find evidence of life in the oceans of both Europa and Enceladus and we decide to send human missions to investigate those life forms ASAP?

For human long haul missions across our Solar System we could use super high specific impulse nuclear pulse rocket systems to get us safely and quickly where we want to go in an affordable manner.

A large Orion type of nuclear pulse powered spaceship launched from the Moon, or Lunar orbit, to Europa or Enceladus could avoid the Earth’s magnetosphere and thus radiation from the nuclear pulses would not contaminate the Earth.

“Orion reacts small directional nuclear explosives against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximize the momentum transfer, leading to specific impulses in the range of 6,000 seconds, or about thirteen times that of the Space Shuttle Main Engine. With refinements a theoretical maximum of 100,000 seconds (1 MN•s/kg) might be possible. Thrusts were in the millions of tons, allowing spacecraft larger than 8 × 10⁶ tons to be built with 1958 materials.”

And, “The same craft could visit Saturn’s moons in a seven-month mission (compared to chemically powered missions of about nine years).”

Industrialize the Moon and humans and our robots could use those Lunar industrial capabilities to build and launch large, efficient, and reusable Orion nuclear pulse spaceships with the effective amounts of radiation shielding that is needed to fly risk minimized and quick missions to Europa, Enceladus, and elsewhere across our enormous, interesting, and resource rich Solar System.

But a human expedition to Europa makes little sense. Even if sufficient shielding can be assembled to reduce exposure of crew to acceptable levels, they could not leave the vessel. We’re in no danger of fabricating EVA suits, or even rovers, which can achieve that level of shielding. A lander would likewise require mass prohibitive levels of shielding. The only value a crew could provide might be teleoperation of surface rovers or drones. That might have some very modest value, but for a “quick” mission, you would get little teleoperation bang for your buck. And it would require a lot of bucks to get that crew to Europa.

(Callisto with its 0.01 rem per day , on the other hand, might be another story.)

No matter how much we industrialize the Moon, I think the next century – probably much longer – of human exploration of Europa is going to have to be done solely with robotic probes.

I consider it likely that the Orion propulsion concept will suffer the same fate as the Tesla turbine. Something that is state of the art when proposed becomes overtaken by other technologies a few decades late. Just as turbine blade technology advanced to obsolete the disk, other high impulse/low consumption technologies will obsolete Orion.

Of course. The Orion nuclear pulse spaceship is fun to contemplate for the same reason a ’59 Cadillac with big tail fins or a hula hoop is fun, nostalgia for a simpler time.
“Fun to contemplate” is just fine, but it’s childish and beyond ludicrous to use words like “doable” and “affordable” regards giant spaceships fueled with thousands of nuclear bombs built in Moon factories.

Orion would have been pretty good at hoisting huge payloads OFF the Earth (ignoring the radioactive fallout), but Orion’s so-so effective exhaust velocity and horrible thrust to weight would make it a not-so-good IN space ship (not to mention the hideous mechanical complexity).

In the modern era, the nuclear salt water rocket renders the Orion concept 100% obsolete.
Below is a link to Cramer’s Analog column on the nuclear salt water rocket:

Thanks for that link. One of the many possibilities for serious future propulsion. Perfectly illustrates the point I was trying to make. Any technology can be overtaken by further developments. “We don’t need telephones because we have plenty of messenger boys.” by some well forgotten official.

“-it’s childish and beyond ludicrous to use words like “doable” and “affordable”-”

It is in reality quite doable and affordable considering the data on over 1000 nuclear detonations and decades of supercomputer weapon simulations since. Quite doable and affordable considering several hundred tons of bomb grade uranium and plutonium in stockpiles around the world that nobody knows what to do with. It takes less than 8 pounds of fissionable material to make a bomb. Freeman Dyson’s calculations show exactly the opposite of what you are blabbering.

“The Compton–Belkovich Thorium Anomaly was found in 1998 by the Gamma Ray Spectrometer (GRS) instrument on board the Lunar Prospector (LP) and subsequently identified as a hotspot, located around 61.1°N 99.5°E.[2] The estimated thorium concentration reaches 5.3 µg/g (5.3 micrograms per gram) while the surrounding highland basalts only contain between 0 and 2 µg/g. Compared to the Earth’s thorium concentration of 0.06 µg/g, the Compton–Belkovich’s is very high.

There is obviously lots of thorium on the Moon. And confused comments like this one by se jones are beyond foolish:

“An Orion would require the manufacture and launch of thousands of nuclear bombs.” – se jones

Wrong.

Why?

Every nuclear material we really need to build, fuel, and test various types of Orion nuclear pulse spaceships on the Moon or in Lunar orbit can be found or made on the industrialized Moon.

Note:

“In 1946 the public first became informed of uranium-233 bred from thorium as ‘a third available source of nuclear energy and atom bombs’ (in addition to uranium-235 and plutonium-239), following a United Nations report and a speech by Glenn T. Seaborg.”

And, “The United States produced, over the course of the Cold War, approximately 2 metric tons of uranium-233, in varying levels of chemical and isotopic purity.”

And, “The long-term strategy of the nuclear power program of India, which has substantial thorium reserves, is to move to a nuclear program breeding uranium-233 from thorium feedstock.”

I am getting a bit old and expect to be long dead before the Lunar Compton–Belkovich Thorium Anomaly is mined, the Moon is industrialized, and Orion super high Isp nuclear pulse propulsion spaceships of various types and sizes get built and tested there or in Lunar orbit.

Nonetheless, that is a useful and doable Lunar ‘roadmap’ with the potential for lots of national and international business investments that could eventually also enable the building of mining bases and various types of colonies at Ceres, 16 Psyche, Europa, Callisto, Enceladus, and elsewhere across our Solar System.

Lunar industrialization will initially be a slow process.

However, there is the possibility that Jeff Bezo’s ongoing serious investments in providing routine access to the Moon with Blue Origin’s Blue Moon lunar lander and New Glenn launcher along with the significant capabilities of the SLS and International Orion could serve to stimulate and accelerate massive amounts of national and international business investment in finding and tapping Lunar resources and industrializing the Moon and the rest of Cislunar Space.

That is why I respect and love the SLS, International Orion, New Glenn launcher, and Blue Moon lunar lander.

The governments of Europe, Russia, India, China, Japan, North Korea, South Korea, Pakistan, Egypt, Nigeria, South Africa, Canada, Mexico, Brazil, Singapore, and many other countries could also be eager to use their various launchers, spacecraft, robotic capabilities, or many diverse intellectual assets to get fully involved with and accelerate that Lunar resource finding and mining process and the critically important industrialization of the Moon and the rest of Cislunar Space in order to make money and benefit the Home Planet folks and environment.

(Callisto with its 0.01 rem per day , on the other hand, might be another story.) – Richard Malcolm

Send some robotic missions to Callisto.

Folks have given some serious thought to a human mission to Callisto:

“This paper summarizes the content of a NASA-led study performed to identify revolutionary concepts and supporting technologies for Human Outer Planet Exploration (HOPE). Callisto, the fourth of Jupiter’s Galilean moons, was chosen as the destination for the HOPE study. Assumptions for the Callisto mission include a launch year of 2045 or later, a spacecraft capable of transporting humans to and from Callisto in less than five years, and a requirement to support three humans on the surface for a minimum of 30 days.”

And, “Time away from the safety of Earth needs to be minimized because of exposure to the deep space radiation environment, microgravity effects and the raw amount of consumables (food, water, air) that the crew requires.”

Right now we need to continue to quickly expand our diverse spacefaring capabilities at the permanent ISS and on the industrialized Moon.

“’The life support system on the station today is not of the reliability or the low maintenance that is needed for a Mars-class mission,’ Gerstenmaier said March 30. ‘We need to really step that up. A great place to test that, in fact the only place to really test that kind of stuff, is on-board the space station.’”

Large, affordable, doable, and highly efficient Orion nuclear pulse spaceships launched from the Moon or Lunar orbit could offer both artificial gravity options and significant amounts of massive and highly effective radiation shielding that could enable a wide diversity of deep space missions and colonies while also providing the robust means to divert large asteroids or comets away from impacting the Earth.

“Just as turbine blade technology advanced to obsolete the disk, other high impulse/low consumption technologies will obsolete Orion.” – john hare

And that new “high impulse/low consumption technologies”, whatever it someday is, could be great!

Nonetheless:

“The project code-named Orion, featured an extraordinary propulsion method known as Nuclear Pulse Propulsion. The concept is probably as radical today as it was at the dawn of the space age. However, its development appeared to be so promising that it was only by political and non-technical considerations that it was not used to extend humanity’s reach throughout the solar system and quite possibly to the stars.”

Even metallic hydrogen with an Isp around 1,700 is far less than the “6,000” to “a theoretical maximum of 100,000” Isp that nuclear pulse systems can offer.

Do we humans really want to go to Mars, Ceres, Europa, Callisto, Enceladus and the “200 dwarf planets in the Kuiper belt of the outer Solar System[1] and possibly more than 10,000 in the region beyond”?
Quote from: ‘List of possible dwarf planets’ Wikipedia

Lots of doable nuclear pulse propulsion system possibilities exist. And many destinations across our Solar System will be within our spacefaring capabilities once we have an industrialized Moon.

“I consider it likely that the Orion propulsion concept will suffer the same fate as the Tesla turbine.”

I consider it likely this guy has no idea what he is talking about. There is no similarity between a steam turbine patent, not in any way, to a nuclear device propelling a spacecraft. Again, contrarians deserve to be ignored and laughed at.

James – your point on the idustrialization of the Moon underscores the need to test technologies to be used in future missions to Mars, Callisto, Europa, etc. We need these experiences before any such undertakings while allowing time for the advanced propulsion systems to develop and mayure.

“A nuclear salt-water rocket (NSWR) is a theoretical type of nuclear thermal rocket which was designed by Robert Zubrin.[1] In place of traditional chemical propellant, such as that in a chemical rocket, the rocket would be fueled by salts of 20 percent enriched uranium or plutonium. The solution would be contained in a bundle of pipes coated in boron carbide (for its properties of neutron absorption). Through a combination of the coating and space between the pipes, the contents would not reach critical mass until the solution is pumped into a reaction chamber, thus reaching a critical mass, and being expelled through a nozzle to generate thrust.”

If we really want to go to Ceres, Vesta, 16 Psyche, Europa, Callisto, Enceladus, and many of the possible thousands of dwarf planets in the outer Solar System, such nuclear salt-water rocket propulsion systems and “New Orion: Pulsed Nuclear Space Propulsion Using Photofission Activated by Ultra-Intense Laser” types of systems and various other such nuclear propulsion systems would need to be tested on the Moon or in Lunar orbit in order to avoid the Earth’s magnetosphere so that radiation from such powerful and super high Isp nuclear propulsion systems would not contaminate the Earth.

Industrializing the Moon will enable safe and politically accepted tests for a wide variety of powerful nuclear propulsion systems and offer many other excellent opportunities to humans including robust defense systems to protect the Earth against incoming NEOs, Space Based Solar Power Systems, permanent enormous optical and radio telescopes, lunar electromagnetic launch systems to send cargo to Earth and Mars and Ceres, and many construction options for building large and highly capable spacecraft that can provide risk minimized and fast human spaceflights across our Solar System.

Eventually, we could even build super enormous O’Neil cylinder types of space habitats in Lunar orbit that could travel to orbits around Ceres, Vesta, 16 Psyche, Mars, Europa, Callisto, and Enceladus to tap their resources and other opportunities.

The problem with Zubrin’s idea is the same problem Nuclear Thermal Rockets have- internal temperatures are far beyond anything matter can hope to contain and are inherently inefficient compared to external pulse. Nuclear pulse impinges on the material surface of the plate momentarily and then the material cools. It is a simple enough principle to understand but we are conditioned to think of it as somehow being primitive and inefficient when in reality the opposite is true. People like Stan Ulam and Freeman Dyson- true geniuses- did not have any problems accepting it as valid.

In the salt-water-rocket, the high pressure jet of fissionable liquid skews the neutron flux to the outside of the reaction chamber, where the neutrons and radiative flux are absorbed by the torrent of ordinary water that is injected downstream of the reaction. The physical structure of the engine is never exposed to the continuous nuclear detonation, the salt water rocket is essentially a nuclear steam engine using transpiration cooling of the nozzle.

Nuclear Thermal Rockets use regenerative cooling of the convergent-divergent nozzle (using liquid hydrogen) just like any high performance rocket engine. The nuclear core, pressure shell and reflector are kept below their critical buckling temperature by the flow of the liquid hydrogen -which is the whole point of the engine. The hydrogen reaction mass is heated to by the reactor core to ≈5000°F, a temperature which the fuel rods and other components are designed to handle.

The solid core NERVA / ROVER nuclear engines were taken to technology readiness level 6 (ready for flight test) back in the late 1960s early 70s. The NERVA program was by any measure one of the most successful pure technology development programs in US history. In the early 1970s the XE engine in flight configuration ran at full thrust for nearly two hours, at over twice the specific impulse of the Shuttle RS-25. In other tests XE demonstrated 28 restarts on the same engine, using “bootstrapping” where the reactor core heat starts the turbo-pumps, without an external spool-up force.

Now…all this is public domain knowledge, there are lots of YouTube videos of the NERVA Engine testing at Jackass Flats Nevada. So, for someone to say “internal temperatures are far beyond anything matter can hope to contain”, shows an 8th grader level understanding of the subject and/or the dishonest, deranged mind of a Gary Church sock puppet.

think of it (nuclear pulse) as somehow being primitive and inefficient

Well it is, in fact, primitive and inefficient, it’s a 1950s idea. Again, used IN space, the Orion has poor performance from a low effective exhaust velocity and a horrible thrust to weight. And worse, a space vehicle is the tip-of-the-spear of a huge industrial base and program infrastructure. An Orion would require the manufacture and launch of thousands of nuclear bombs. Now, an 8th grader can’t conceive of those “minor” details, but I leave it to the grown-ups to imagine the issues.

The nuclear salt water rocket would be orders of magnitude more efficient than a “pulse”, a 20% enriched salt water engine making a jet power of 427 gigawatts with 12.9 meganewtons thrust, at a reasonable thrust-to-weight ratio of 40, all the fission energy goes into the exhaust and the engine itself with fission fuel, is fairly lightweight.

A salt water rocket need not worry about fission fragments in the Earth’s magnetosphere, the engines’s 69,000 m/s exhaust velocity exceeds the escape velocity of the SOLAR SYSTEM.

Now…a nuclear salt water rocket DOES need extraterrestrial infrastructure to be feasible, and that cost must be factored in. The extraterrestrial infrastructure would be Lunar polar water, for reaction mass. This is why the usual suspects should embrace the salt water rocket, instead of constantly wasting Americaspace’s bandwidth with the same old 1950s Orion Pulse quasi-religious dogma. In the midterm-future (a few decades?) our descendants might actually BUILD a nuclear salt water rocket, whereas Orion will always be a retro 50s fantasy.

“The nuclear salt water rocket would be orders of magnitude more efficient than a “pulse”-”

Except there is no such rocket while the technology for pulse is…well, orders of magnitude more developed- and the imaginary rocket would not be orders of magnitude more efficient even if such a nightmare could be made to work.
Stop making stuff up.

The usual suspects should embrace Nuclear Thermal Rocket (NTR) engines as well. Why? Well because, in the the near(ish) term (about decade?) liquid oxygen from the Moon can make the NTR even better.

A low enriched NTR like the one NASA Marshall is working on, will have a specific impulse about twice as good as the RS-25. But (there’s always a but) the NTR suffers from not-so-great dry mass, because the reactor core is heavy, and the tanks to hold the low density liquid hydrogen reaction mass are quite large (and may require a cryocooler).

A way to improve the NTR is to add a liquid oxygen (LOX) “afterburner” to the NTR hydrogen exhaust nozzle. This is called a LOX-Augmented Nuclear Thermal Rocket (LANTR). The vehicle gets lots more thrust while it burns LOX with the hot hydrogen exhaust from the reactor. The LOX-Augmented boost phase happens in Low Earth Orbit (LEO), while the vehicle is travelling fastest deep in Earth’s gravity well. When you light-em-up deep in LEO, you take advantage of the Oberth Effect.

Oberth Effect? I leave it to readers to Google it, but in simple terms: every child who’s ever been on a swing set, knows intuitively what the Oberth Effect is, without knowing what it’s called. You pump low to mid swing swing when you’re moving fastest, not when your at the top of the ark. In a related manner, when you burn a rocket engine when you’re deep in a gravity well (perihelion) you gain (steal) more velocity change from the system. (this yet another reason Orion pulse stinks, you can never use it close to Earth, so you loose all potential Oberth Effect)

A way to make the LOX-Augmented Nuclear Thermal Rocket (LANTR) even more attractive, is to ship liquid oxygen (LOX) down to LEO from the Moon. Getting LOX from the Moon is a sure and easy thing compared to ice from the Lunar poles. Moon rocks (like most rocks) are mostly silicon dioxide by mass, so heat up moon rocks in a solar furnace and collect the oxygen. Liquid oxygen is easy to store and transfer (compared to hydrogen), so the whole process is more economically feasible for early Lunar ISRU.

Mining Ice, processing the Ice, getting the LH2 & LOX down to LEO where it’s most needed, is not as easy (or as economical) as some would want to believe.

(this yet another reason Orion pulse stinks, you can never use it close to Earth, so you loose all potential Oberth Effect) – se jones

Wrong.

A spaceship with an Orion nuclear pulse propulsion system or some other type of super high Isp nuclear propulsion system could, if need be, make use of the gravity wells of the Moon, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and maybe even the Sun.

Using the Oberth effect will not always be a critical issue for spaceships using super high Isp nuclear propulsion systems like Orion to enable risk minimized fast trips across our Solar System from a very wide diversity of starting points that often won’t be near the Moon or any significant gravitational well and to the many destinations that also often won’t be near any major gravitational well.

“Orion is one of very few interstellar space drives that could theoretically be constructed with available technology, as discussed in a 1968 paper, Interstellar Transport by Freeman Dyson.”

And, “Medusa performs better than the classical Orion design because its sail intercepts more of the explosive impulse, its shock-absorber stroke is much longer, and all its major structures are in tension and hence can be quite lightweight. Medusa-type ships would be capable of a specific impulse between 50,000 and 100,000 seconds (500 to 1000 kN•s/kg).

And, “Medusa is widely known to the public in the BBC documentary film To Mars By A-Bomb: The Secret History of Project Orion.[12]”

And, “In the mid-1990s research at the Pennsylvania State University led to the concept of using antimatter to catalyze nuclear reactions. In short, antiprotons would react inside the nucleus of uranium, causing a release of energy that breaks the nucleus apart as in conventional nuclear reactions. Even a small number of such reactions can start the chain reaction that would otherwise require a much larger volume of fuel to sustain. Whereas the ‘normal’ critical mass for plutonium is about 11.8 kilograms (for a sphere at standard density), with antimatter catalyzed reactions this could be well under one gram.”

Industrializing the Moon will enable the testing of many doable and robust transportation options in space including various types of super high Isp Orion nuclear pulse propulsion systems that could take humans on fast and risk minimized trips to Mars, Ceres, Vesta, 16 Psyche, Europa, Callisto, Enceladus, Pluto, and maybe even to far distant star systems.

In 2003, at Holloman Air Force Base, a rocket sled achieved a 2.86 km/s velocity.

“Electrodynamic tethers (EDTs) are long conducting wires, such as one deployed from a tether satellite, which can operate on electromagnetic principles as generators, by converting their kinetic energy to electrical energy, or as motors, converting electrical energy to kinetic energy.[1] Electric potential is generated across a conductive tether by its motion through a planet’s magnetic field.”

And, “As part of a tether propulsion system, crafts can use long, strong conductors (though not all tethers are conductive) to change the orbits of spacecraft.”

And, “It can be used either to accelerate or brake an orbiting spacecraft.”

Atmospheric aerobraking and electrodynamic tether technology can be used lower and adjust the Earth orbits of our propellant and other resource carrying spacecraft.

Mining Lunar ice and other useful Lunar resources and moving them to elliptical Earth orbits and eventually to circular high or low Earth orbits is a whole lot technologically easier, less risky, cheaper, and much more useful for the Home Planet than trying to build high risk, uneconomical, and burdensome colonies on far distant Mars.

And no one seems to think that building super high Isp Orion nuclear pulse spaceships on Mars or in Mars orbit anytime soon would be easier than building them on, or in orbit of, the industrialized Moon.

The industrialized Moon and building and testing Orion spaceships on the Moon or in Lunar orbit could allow us to go fast to everywhere in the Solar System, including Mars, Ceres, Vesta, 16 Psyche, Europa, Callisto, Enceladus, and Pluto. That Orion transportation option could be a super deal for everyone on the Home Planet.

“An Orion would require the manufacture and launch of thousands of nuclear bombs. Now, an 8th grader can’t conceive of those “minor” details, but I leave it to the grown-ups to imagine the issues.” – se jones

Wrong.

“Schwoerer et al. exhibited photofission using a tabletop laser capable of achieving an intensity on the order of 10 20 W/cm2. The experimental process incorporated two sheets of tantalum before the uranum-238 target. The preliminary tantalum sheet approximately 50 μm thick is used to generate a hot plasma. The subsequent tantalum sheet with a thickness of 1mm functions as a bremsstrahlung converter as plasma accelerated electrons from
the first sheet strike the second sheet [12]. There are many advantages to applying photofission for nuclear pulsed space propulsion.

Photofission has been demonstrated by readily available sources, such as natural uranium isotopes, lead, and thorium [13] [14].”

And, “Fundamental performance analysis of Project New Orion establishes the capability to impart a meaningful velocity increment on a small spacecraft through ultra-intense laser
derived photofission.”

Lots of nuclear pulse propulsion systems and other powerful nuclear propulsion systems could probably eventually work just fine.

The critical political point is that the large reusable spaceships using various powerful super high Isp nuclear propulsion systems could be extensively tested, and ‘home based’, on the industrialized Moon or in Lunar orbit in order to avoid the risk of radiation contaminating the Earth.

If we really want to tap the resources and other opportunities of Ceres, Vesta, 16 Psyche, Europa, Callisto, Enceladus, and many of the possible thousands of dwarf planets in the outer Solar System, we should industrialize the Moon ASAP.

James, if you want to be taken seriously, you’ve got to be honest and somewhat consistent.

YOU started this exchange with a post on, and I quote: “Orion reacts small directional nuclear explosives against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximize the momentum transfer, leading to specific impulses in the range of 6,000 seconds, or about thirteen times that of the Space Shuttle Main Engine. With refinements a theoretical maximum of 100,000 seconds (1 MN•s/kg) might be possible. Thrusts were in the millions of tons, allowing spacecraft larger than 8 × 10⁶ tons to be built with 1958 materials.”From: ‘Orion: Nuclear Pulse Propulsion’ By William-Black At: https://william black.deviantart.com/journal/Orion-Nuclear-Pulse-Propulsion-393051331

1958 materials not 21st century materials.

This Deviant Art journal 1950’s Orion is NOT the same thing as “New Orion Photo fission…thing”. You are moving the goal posts and trying to change the subject after I called BS. Sorry, you’re too transparent. I give you a D- in debate class pal.

Anyway, on the plus side, this “Project New Orion” uses lots of unobtanium, but no actual handwavium.

Everyone has seen the classic Sidney Harris cartoon: “then a miracle occurs” http://www.sciencecartoonsplus.com/pages/gallery.php
Well, in this “Project New Orion” an engineering miracle occurs just about every paragraph; flight weight superconducting magnets –then a miracle occurs flight weight Magneto-Hydrodynamic Generators –then a miracle occurs 95% combustion
efficiency producing a thermal power of 95MW –then a miracle occurs flight weight lasers on the scale of 10^20 W/cm2 –then a miracle occurs and so on.

The ultimate –then a miracle occursunobtanium (that boarders on handwavium) is your very own “James Industrializing the Moon”. Everything is easy if we just “Industrialize the Moon”. $Trillions of dollars in fundamental physics research at Los Alamos and Lawrence Livermore National Laboratories?? Na…just “Industrialize the Moon”, –then a miracle occurs. Hundreds and hundreds of $billions in fundamental aerospace engineering? Nope, just Industrialize the Moon and –then a miracle occurs.

Don’t get me wrong, Old Orion, New Orion, Nuke Salt Water, Antimatter…none of it is impossible if it doesn’t violate the laws of nature, our far future robot AI overlords can design and build whatever we want, if we can control them. But fantastic super atomic rockets won’t happen in the NEAR term as you always seem to preach.

James, if you want to be taken seriously, you’ve got to be honest and somewhat consistent.

YOU started this exchange with a post on, and I quote: “Orion reacts small directional nuclear explosives against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximize the momentum transfer, leading to specific impulses in the range of 6,000 seconds, or about thirteen times that of the Space Shuttle Main Engine. With refinements a theoretical maximum of 100,000 seconds (1 MN•s/kg) might be possible. Thrusts were in the millions of tons, allowing spacecraft larger than 8 × 10⁶ tons to be built with 1958 materials.” From: ‘Orion: Nuclear Pulse Propulsion’ By William-Black At: https://william black.deviantart.com/journal/Orion-Nuclear-Pulse-Propulsion-393051331

1958 materials not 21st century materials.

This Deviant Art journal 1950’s Orion is NOT the same thing as “New Orion Photo fission…thing”. You are moving the goal posts and trying to change the subject after I called BS. Sorry, you’re too transparent. I give you a D- in debate class pal.

Anyway, on the plus side, this “Project New Orion” uses lots of unobtanium, but no actual handwavium.

Everyone has seen the classic Sidney Harris cartoon: “then a miracle occurs” http://www.sciencecartoonsplus.com/pages/gallery.php
Well, in this “Project New Orion” an engineering miracle occurs just about every paragraph; flight weight superconducting magnets –then a miracle occurs flight weight Magneto-Hydrodynamic Generators –then a miracle occurs 95% combustion
efficiency producing a thermal power of 95MW –then a miracle occurs flight weight lasers on the scale of 10^20 W/cm2 –then a miracle occurs and so on.

The ultimate –then a miracle occurs unobtanium (that boarders on handwavium) is your very own “James Industrializing the Moon”. Everything is easy if we just “Industrialize the Moon”. $Trillions of dollars in fundamental physics research at Los Alamos and Lawrence Livermore National Laboratories?? Na…just “Industrialize the Moon”, –then a miracle occurs. Hundreds and hundreds of $billions in fundamental aerospace engineering? Nope, just Industrialize the Moon and –then a miracle occurs.

Don’t get me wrong, Old Orion, New Orion, Nuke Salt Water, Antimatter…none of it is impossible if it doesn’t violate the laws of nature, our far future robot AI overlords can design and build whatever we want, if we can control them. But fantastic super atomic rockets won’t happen in the NEAR term as you always seem to preach.

“Well, in this ‘Project New Orion’ an engineering miracle occurs just about every paragraph” – se jones

Industrializing the Moon is far more doable and offers nuclear propulsion options along with many more useful business, scientific, and security opportunities for the Home Planet than your super risky and zip business case ‘Project Mars Now via chemical rocket’ “handwavium” nonsense fantasies you have been pushing with your nasty snake oil sarcasm on this website.

Orion’s main issue was, and is, political not technical. All your squawking and quacking about how tapping Lunar resources and building nuclear pulse propulsion systems are so difficult makes Mars colonies appear even more risky, difficult, costly, and useless than they probably are.

Grow up. Mars was never on the table. You’ve been conned by an oddball former President who had zip interest in human missions to Mars or anywhere else and his political friend who is a business person that doesn’t really want to go to Mars and simply has a history of using government subsidies to make money.

Get over your childish hate for the Moon and its resources and the SLS and International Orion Cislunar transportation system that has far more technical, political, and economic support than anything you have posted about.

Nuclear Orion propulsion systems can be tested on the industrialized Moon and offer far more Isp and long haul options across our enormous Solar System than your ‘Martian friend’s’ weak chemical rocketry and nothing you can loudly proclaim can change that simple and basic fact.

It is not likely that any “advanced propulsion system” can compete with the Orion concept Tom.

Not for a long time to come.

“The Isp attainable is proportional to the product of the propellant impingement velocity against the pusher plate and the fraction of pulse unit mass striking it. The impingement velocity is limited by pusher plate ablation and is probably in the range of 100 to 200km per second. The pulse unit fraction is determined by design of the explosive charge and the stand-off distance and is in the range of 1O percent to 50 percent. The resulting Isp limits are approximately 3.000 to 10,000 seconds.”

I corresponded with Bonometti about a decade ago concerning pulse propulsion and I suspected what he could not say in his paper was that classified research on directed energy weapons (star wars) means the fraction of pulse unit as plasma striking the pusher plate would be far higher and at lower temperatures. This would put Isp’s in the tens of thousands. The key to understanding why pulse has no competition is as it scales up the efficiency multiplies. H-bombs require a few tablespoons of tritium and deuterium to increase their energy yield from kilotons to megatons- so the larger the pulse system the more efficient it becomes. Dyson stated there were no obstacles to lifting whole cities off the surface of the Earth into space. There was one obstacle of course- fallout. Launching from the Moon, outside the magnetosphere, removes that obstacle.

“Dyson stated there were no obstacles to lifting whole cities off the surface of the Earth into space. There was one obstacle of course- fallout. Launching from the Moon, outside the magnetosphere, removes that obstacle.” – MichaelatNASA

The comments don’t matter to you then this is what you get- a couple poisonous harassers that are happy no one says anything except them. There should be no problem when those being insulted call it what it is.

Your comments are being hit by our automatic spam filters and held for approval. Personally I have better things to do with my time than babysitting comments and moderating debates between readers, only when I have the free time will I actually moderate comments, which is rare. Your comments are approved as soon as I see they are being held, apologies for the issue but that’s the explanation.

Given some of the content in comment threads, I’m surprised that yours is awaiting moderation. I would be interested in knowing what the policies are if moderation is going to be effective going forward.

“The Russian “Lego” approach to building heavy-lift rockets will also make it possible to fly lighter and heavier variants of the rocket. By attaching either two or six strap-on boosters to the core stage, the payload capacity can be reduced to around 70 tons or increased to 170–180 tons.”

Such a powerful and mission capable heavy-lift launcher family could enable Russia to do joint robotic lander missions with other countries interested in the Ocean Worlds of Europa and Enceladus.

This Russian heavy-lift launcher family would make efficient use of varying numbers of the powerful and efficient RD-171M rocket engine with more than 1,600,000 lbs of thrust at sea level and a vacuum Isp of 338 and should also enable the adding of new and very large modules to the International Space Station and the leadership of various types of international human and robotic Lunar exploration, mining, industrialization, and other missions to make effective use of our Moon and its many diverse resources and opportunities.

“The RD-170 (РД-170, Ракетный Двигатель-170, Rocket Engine-170) is the world’s most powerful liquid-fuel rocket engine, designed and produced in the Soviet Union by NPO Energomash for use with the Energia launch vehicle. The engine burns the Russian equivalent of RP-1 fuel and LOX oxidizer in four combustion chambers, all supplied by one single-shaft, single-turbine turbo pump rated at 170 MW in a staged combustion cycle.”

And, “Building on the technology from the Energia launch vehicle the Zenit (rocket family) was developed, which uses a RD-170 variant, the RD-171. While the RD-170 had nozzles which swiveled on both axes, the RD-171 swivels on just one axis.[2] RD-171 was intended to be used on Zenith rocket, and one-axis swiveling allowed to avoid additional aerodynamic forces. Models called the RD-172[citation needed] and RD-173 were proposed upgrades that would provide additional thrust, and the RD-173 proposal was finalized as the RD-171M upgrade in 2006.”

It also seems likely that leaders in Russia, Europe, India, China, Brazil, Japan, North Korea, South Korea, South Africa, and many other places can see the real Home Planet economic, scientific, technological, and security benefits and opportunities of building and testing Orion nuclear pulse spaceships on the Moon, or in Lunar orbit, even if many American leaders remain ignorant or in denial of those real benefits and opportunities.

Our Solar System will de facto belong to those nations, companies, and individuals that can work together on the Moon and in Lunar orbit to build, test, and fly the super high Isp nuclear powered spaceships that can efficiently and quickly travel the enormous distances between the Moon and Europa or Enceladus or the possible thousands of dwarf planets orbiting in the outer regions of our Solar System.